The aim of this meeting is to bring together scientists studying peptide processing enzymes and intracellular sorting mechanisms from biochemical, cell biological, developmental, and genetic perspectives so that a more comprehensive understanding of the processes will emerge. The range of topics to be covered at this meeting will be a tremendous learning experience that will benefit both junior scientists (students and post- docs) as well as established scientists. Also, this meeting will be held concurrently with a highly related Keystone meeting, and the joint format will produce a large number of multidisciplinary interactions. Many biologically important proteins and peptides are synthesized as inactive precursors that require proteolytic cleavage to become biologically active. Recent advances have led to the identification of several enzymes responsible for these activation steps, and the mechanism by which proteins are targeted to the correct cellular organelle where proteolytic processing occurs. In addition, genetic defects with some of the processing enzymes have recently been identified in humans, mice, and in lower organisms; these defects cause a variety of physiological changes including obesity, sterility, and diabetes. Inhibitors of the processing enzymes are being developed for a wide range of applications including antiviral agents, antihypertensives, analgesics, and chemotherapeutics. To understand the complex systems of protein and peptide processing, a wide array of approaches are needed. One important aspect of this meeting will be to bring together scientists from different fields, who are working on the same problems, but using different techniques. Students, post-docs, and established scientists will benefit from the exposure to different systems, and the potential for collaborations; through collaborations, research can be conducted more efficiently, and so NIH funding is well justified for the meeting.